Halliday & Matthiessen (2014: 426):
If prepositional phrases are interpreted as ‘compressed’ or ‘shrunken’ clauses with the structure of Predicator/Process + Complement/Range, then it makes sense to ask whether alongside these ‘ranged’ phrases, there are ‘non-ranged’ ones: this is a question that arises automatically from our clause-like analysis of prepositional phrases. Consider an agnate pair of clauses such as he crossed and he crossed the street. Here the agnation has to do with the absence or presence of the Range; the two clauses are ‘non-ranged’ and ‘ranged’, respectively. Are these two clauses analogous to a pair of phrases such as across and across the street? In other words, is there a proportion:he crossed : he crossed the street ::
(he walked) across : (he walked) across the street
If there is, this would mean that in traditional terms prepositions can be either intransitive (across) or transitive (across the street). … In discussing prepositions and adverbs, Jespersen (1924: 88) suggests that there is an ‘exact parallel’ between examples such as put your cap on and put your cap on your head, on the one hand, and he was in and he was in the house, on the other. More recently, in their reference grammar of English, Huddleston & Pullum (2002: 612 ff.) argue that certain ‘adverbs’ should be analysed as prepositions without ‘NP complements’; for example, they show that in belongs to the same category in the owner is not in and in the owner is not in the house. In our terms, this would mean that prepositional phrases can be ‘non-ranged’ (in) as well as ‘ranged’ (in the house).
Note that Pullum argued on Australian Radio that bush in go bush is a new Australian preposition. Unsurprisingly, he did not produce any prepositional phrases with bush as minor Predicator/Process.